Cross-site comparisons of leaf litter decomposition rates

Background/Question/Methods Fresh litter from the most dominant plant species at each of 5 LTER sites (list) was analyzed by reciprocal transplantation for rate of initial decomposition (4 months duration, mid-winter through spring) at each of the 5 environments. 

Results/Conclusions

All litter of plant species at all sites demonstrated an increase in C:N ratio as an outcome of both respiration and import/translocation by invading fungi. The decrease in C:N ratio with 4 months of decomposition was mesquite(NM) > bougainvillea(AZ) > Douglas-fir(OR) > red alder(OR) > grama grass(CO)  > Cecropia(PR). This relative ranking was identical at the 5 different ecosystems, implying that microbial flora was not preadapted at any site for the dominant litter type therein. Ambient temperature was presumably the primary driver with Puerto Rico rain forest > Oregon rain forest > Colorado grassland > urban Arizona desert > Chihuahuan desert; each litter species followed this same pattern.